This disclosure describes techniques that include collecting underlay flow data within a network and associating underlay flow data with a source and a destination virtual network to enable insights into network operation and performance. In one example, this disclosure describes a method that includes identifying, for each underlay data flow, a source overlay network and a destination overlay network associated with the underlay data flow, wherein identifying includes retrieving, from one or more Ethernet Virtual Private Network (EVPN) databases, information identifying the source and destination overlay networks.